Scientists claim big leap in nanoscale storage

Stephen Lawson |
Feb. 20, 2009

Scientists say they have achieved a breakthrough that could fit the contents of 250 DVDs on a coin-sized surface.

SAN FRANCISCO, 19 FEBRUARY 2009 - Nanotechnology researchers say they have achieved a breakthrough that could fit the contents of 250 DVDs on a coin-sized surface and might also have implications for displays and solar cells.

The scientists, from the University of California at Berkeley and the University of Massachusetts Amherst, discovered a way to make certain kinds of molecules line up in perfect arrays over relatively large areas. The results of their work will appear Friday in the journal Science, according to a UC Berkeley press release. One of the researchers said the technology might be commercialized in less than 10 years, if industry is motivated.

More densely packed molecules could mean more data packed into a given space, higher-definition screens and more efficient photovoltaic cells, according to scientists Thomas Russell and Ting Xu. This could transform the microelectronics and storage industries, they said. Russell is director of the Materials Research Science and Engineering Center at Amherst and a visiting professor at Berkeley, and Xu is a Berkeley assistant professor in Chemistry and Materials Sciences and Engineering.

Russell and Xu discovered a new way to create block copolymers, or chemically dissimilar polymer chains that join together by themselves. Polymer chains can join up in a precise pattern equidistant from each other, but research over the past 10 years has found that the patterns break up as scientists try to make the pattern cover a larger area.

Russell and Xu used commercially available, man-made sapphire crystals to guide the polymer chains into precise patterns. Heating the crystals to between 1,300 and 1,500 degrees Celsius (2,372 to 2,732 degrees Fahrenheit) creates a pattern of sawtooth ridges that they used to guide the assembly of the block copolymers. With this technique, the only limit to the size of an array of block copolymers is the size of the sapphire, Xu said.

Once a sapphire is heated up and the pattern is created, the template could be reused. Both the crystals and the polymer chains could be obtained commercially, Xu said.

"Every ingredient we use here is nothing special," Xu said.

The scientists said they achieved a storage density of 10Tb (125GB) per square inch, which is 15 times the density of past solutions, with no defects. With this density, the data stored on 250 DVDs could fit on a surface the size of a U.S. quarter, which is 25.26 millimeters in diameter, the researchers said. It might also be possible to achieve a high-definition picture with 3-nanometer pixels, potentially as large as a stadium JumboTron, Xu said. Another possibility is more dense photovoltaic cells that capture the sun's energy more efficiently.